Tumor diagnosis by PET (positron emission tomography) exploits the phenomenon where tumor tissues proliferate rapidly as compared with normal tissues. For example, [18F]-2-fluoro-2-deoxy-D-glucose (hereinafter, abbreviated to [18F]FDG), which is most widely used clinically at present, is a glucose analog, and its use in the diagnosis is based on the fact that the localization of [18F]FDG reflects energy metabolism. Alternatively, L-[11C]methionine (hereinafter, abbreviated to L-[11C]Met), a derivative of a natural amino acid, is also used in tumor diagnosis by PET, which utilizes the fact that the localization of L-[11C]Met reflects amino acid metabolism (see e.g., Non-Patent Document 1).
[Non-Patent Document 1] The Journal of Nuclear Medicine, 1991, Vol. 32, No. 6, p. 1211-1218
[Non-Patent Document 2] The Journal of Nuclear Medicine, 1999, Vol. 40, No. 1, p. 205-212
[Non-Patent Document 3] The Journal of Nuclear Medicine, 1999, Vol. 40, No. 8, p. 1367-1373